Various management frames are used for setup and maintenance of wireless networks and are exchanged between stations (STAs), such as client devices and infrastructure devices, for example, wireless access points and base stations. Management frames are useful for allowing devices to probe and determine certain characteristics about a wireless network, in addition to negotiation of a wireless connection. For example, management frames can be used to determine a presence of a wireless network, such as by use of beacon frames, probe request frames and probe response frames. Other management frames can be used to negotiate certain characteristics of a data connection, such as authentication and association, such as using authentication requests and responses and association request and responses. Other management frames will be known to and understood by the skilled artisan. Management frames may include source and destination address information, such as specified using media access control (MAC) addresses, as well as other information specified by or required by one or more standards. Management frames may be directed to a specific device (unicast), or to any device (broadcast), for example by using MAC addresses, as appropriate.
Management frames generally comply with one or more wireless networking standards, such as an Institute of Electrical and Electronics Engineers (IEEE) standard. For example, useful IEEE standards include, but are not limited to IEEE 802.11 standards, such as IEEE 802.11-2007, IEEE 802.11n, IEEE 802.11ac, and IEEE 802.11-2012. These standards are hereby incorporated by reference. Compliance with a wireless networking standard advantageously allows a wireless device to communicate with other wireless devices also compliant with the same standard.
Beacon frames are typically used to announce a presence of a wireless network. Beacon frames may be periodically transmitted by devices such as access points, range extenders, base stations, and other infrastructure devices. Beacon frames may further include information about the wireless network and/or infrastructure device, such as capabilities, network identifiers, channel/frequency information, supported data rates, and the like.
Probe request frames, also referred to herein as probe requests, are typically used to determine a presence of a wireless network, such as to determine which access points are within range of a client device. Probe requests may include information about the transmitter, typically a client device, such as MAC address information, capabilities, supported data rates, and the like.
A probe request may, for example, identify a target network by as using a network identifier, such as a basic service set identifier (BSSID) or service set identifier (SSID). Such a probe request is referred to herein as a directed probe request. Probe requests may also identify no network identifier. Such a probe request is referred to herein as a null probe request. Network devices typically transmit probe requests periodically when they are not associated with any wireless network, such as to determine if any known or unknown wireless networks are available or within range.
Probe response frames, also referred to herein as probe responses, are typically used by a wireless infrastructure device, such as a wireless access point or base station, to respond to a received probe request. Probe responses may include information about the base station and wireless network, such as capabilities, supported data rates, channel/frequency information, etc., as well as device identifiers identifiers, such as a MAC address, and network identifiers, such as a BSSID or an SSID.
Authentication frames, such as authentication requests and authentication responses, may be used by wireless devices to authenticate one another and/or to confirm encryption. Authentication requests and responses may comply with the simplest system, an open authentication system, or other authentication systems. Authentication frames may identify one or more parameters, such as a network identifier, authentication type, authentication status, etc.
Association frames, such as association request frames (association requests) and association response frames (association responses), are typically used by wireless devices to allocate resources and synchronize network communications, such as to allow for long term and/or repeated network communications. Association requests may include information about the transmitting and receiving devices, such as network identifiers or addresses. Association responses may also include identifying information, such as one or more MAC addresses, BSSIDs, etc., but generally also include information about whether the association is requested or rejected. If the association of a device is accepted, an association response may include an association ID (AID) assigned to the requesting device. Upon receiving an association response with an AID, a client device may be considered to be associated with and/or connected to the wireless access point that transmitted the association response.